Heat wave brings extreme temperatures to more than two dozen states

A heat wave that began in the Midwest on Monday has spread to more than two dozen states across the Midwest, South, and East Coast and is forecast to continue into the Fourth of July weekend. On Thursday the heat index is expected to reach 111 degrees in Philadelphia and Washington, D.C., 110 degrees in Nashville, 108 degrees in Detroit, 106 degrees in Boston, and 102 degrees in Chicago.

New York City is forecast to reach a heat index of 110 degrees, a level recorded only three times in the past 80 years.

Holiday travel and local responses Amtrak canceled more than a dozen trains in the Northeast on Thursday because of the heat. New York City activated its heat emergency plan and opened hundreds of cooling centers. The mayor of New York City asked employers to plan ahead with their teams, build in flexibility, and ensure no one is put at risk during their jobs this week.

Forecast through the weekend On Friday the heat index is forecast to reach 112 degrees in Washington, D.C., 111 degrees in Memphis, 108 degrees in New York, and 105 degrees in Boston. Overnight relief is expected to be minimal. On Saturday the heat index is forecast to reach 107 degrees in Washington, D.C., and 103 degrees in New York.

By Sunday and Monday the strongest heat and humidity are expected to settle over the Southeast, with Raleigh, North Carolina, forecast to feel like 107 degrees and Savannah, Georgia, forecast to feel like 105 degrees. Extreme heat is the deadliest weather-related hazard in the United States.

At least 13,000 Americans have died from heat since 2018, according to Centers for Disease Control and Prevention data.